Have you ever danced with the sparks of fluttering fluorescence which glows brighter with the dwindling light after a rainy season… with ‘fireflies’. Each one of us has amazed by those at least once in our lives. Not only the fireflies, there are several hundreds of insects, marine vertebrates, invertebrates and microorganisms. This phenomenon is called Bio-luminance, and it is defined as the production and emission of light by a living organism. Most bioluminescent animals are found in the ocean.
These bioluminescent marine species including fishes like anglerfish, lantern fish, flashlight fish and many other deep-sea inhabitants. Certain jellyfishes, vampire squids, some molluscs, sea pens, algae and corals are some marine invertebrates with bio-luminance qualities. Some bioluminescent organisms, including fireflies, glow worms, certain click beetles, centipedes, millipedes and some mushrooms are found on land.
Behind the scene
‘The light’ from their bodies are produced by a chemical reaction. It is a type of chemiluminescence, simply by a chemical reaction light is produced. Fireflies, anglerfish, lantern fish and most other organisms produce the light-emitting pigment called ‘luciferin’ and the enzyme luciferase. Luciferin reacts with oxygen to create blue- greenish light. Bioluminescence is a ‘cold light.’ It means less than 20 percent of the light generates heat.
Depending on the habitat and organism, the appearance of bioluminescent light varies widely. Most marine bioluminescence is expressed in the blue to green. These colors are easily visible in the deep sea. Most land organisms also exhibit yellow-green bioluminescence. Few organisms can glow in more than one color. The head of the larvae called ‘railroad worm’ glows red, while its body glows green. Most organisms, however, emits their lightfor periods of less than a second to about 10 seconds, repeating like flashy fireworks. But the organisms like glowing mushrooms emit light continuously.
Does this glowing do any favor for them? Or is it a just waste of energy to entertain their ‘fans’? Bioluminescence is used by organisms to hunt prey, as a defense mechanism against predators, to find mates, and to execute othervital activities. The most common fireflies light up to attract mates. Although both male and female fireflies can luminesce most flashing fireflies are male. The pattern of their flashes signalsfemale fireflies what type of firefly they are and that they’re interested in mating.
The most eminent predator to use bioluminescence is the anglerfish.it uses bioluminescence to tempt prey. The anglerfish has a huge head, sharp teeth, and a long, fleshy filamenton on the top of its head. On the end of the filament,t there is a ball called ‘esca’ that can be light up. Small fish that are curious about this‘lighting ball’ swim near for a closer look. But it is too late for them to escape from the dark jaws of the enormous predator, behind the‘lighting ball’.
Some animals luminesce to confuse predators. The vampire squid like many other deep-sea squids, lacks ink sacs. Instead, it ejects sticky mucus with bioluminescence, which can frighten, confuse, and delay predators. It allows the squid to escape. Many marine creatures use a technique called counter-illumination to protect them from getting hunted. Many predators like sharks, look above, where sunlight creates shadows beneath prey to figure their presence. Counter- illumination is a type of camouflage resistant to this predatory behavior.
Hatchet fish have light-producing organs whichare pointed downward. They are also able to adjust the amount of luminance coming from their ventral side to match the light coming from above and become virtually invisible to predators looking up. Some of them, such as brittle stars, are able to disengageilluminated body parts to distract predators. So, while the predator follows the glowing arm of the brittle star it crawls away in to the dark, knowing its capability of regenerating it’s the lost arm within months.